You can snowflake the table with countries and start/end of quarters by country with the time dimension (day between start and end). So when you select the country it will automatically join and apply the right filtering on the time dimension based on the country etc.

Proper etiquette is that the poster should provide feedback to those who provide answers to questions; mark responses accordingly as “Correct” or “Helpful.” You can only mark one answer as Correct, though as many as you like as Helpful.

By marking a correct answer in your threads, this will mark the thread as "Answered" and allow members to focus on unanswered questions. If you feel that nothing is particularly correct, then you can just award helpful marks to people, and click the "Mark as Assumed Answered" link on your thread if you now feel there is no need for any further discussion.

By following this etiquette, members are more likely to help you in future (rather than pull you up on the fact you don't do this, as has happened here).